Brake



Nov. 17, 1936.

F. L. o. WADSWORTH 2,060,912

BRAKE Filed July 27, 1932 s Sheets- Sheet 2 IIIIIIIIII ATTORNEY 3Sheets-Sheet 3 ATTORNEY.

FRH/VK L, 17, WHDSWJRTH BRAKE F. L. o. WADSWORTH Filed July 27, 1932Nov. 17, 1936.

Kill!!! I I.

Patented Nov. 17, 1936' UNITED STATES PATENT OFFICE Frank L. 0.Wadsworth, Pittsburgh, 1 s., assigno'r to Bendix Aviation Corporation,South Bend, Ind., a corporation of Delaware Application July 27, 1932,Serial No. 625,113

'1 Claims. (CL 188-452) i A further object of the improvements is to lsecure an automatically controllable regulation of the engagementpressure, and the resultant braking torque at different parts of therelatively movable brake elements. 7

I Another object of this invention is to provide special means formoving expansion members, or elements, into contact with the cooperatingdrum surfacein such manner that the applying force acts at diametrallyopposite points upon the said member.

A further and more specific object of the invention is to provide alinkage whereby fluid pressure may 'be transmitted to an internallyexpansible friction member in the manner and for the purposes aboveindicated.

A further object is to minimize the click or noise resulting from theapplication of the brake elements.

Special features of the invention relate to the use of oval orelliptical fluid pressure cells for applying the friction member to thedrum; the use of linkage adapted to transmit this fluid pressure tothree, four, five, or more, separate and distinct points on the saidmember; and to the use of a cable operated capstan wheel for applyingforce to move the expansible friction member into contact with the brakedrum.

Further objects and features of the invention will be apparent after areading of the subjoined specification and claims and afteraconsideration of the attached drawings, in which? Figure l is asectional elevation of a drum, an internal friction retarding membertherefor and a mechanism for actuating the friction member, allconstructed according to my invention;

Figure 2 is a view in horizontal section showing the fluid pressuremotor used for applying the friction element;

, Figure 3 is a view similar to Figure 1 showing a'modifled form ofactuating mechanism;

Figure 4 is a sectional view taken substantially on the line 4-4 ofFigure 3;

Figure 5 is a sectional elevation, similar to Figure 1 showing the brakedrum, the friction members, and the friction applying means of a 5modification;

Figure 6 is a sectional view through one of the fluid pressure motorsused for applying the friction element to the drum;

Figure 'l is a fragmentary sectional view of a 0 modified form of brakeapplying mechanism.

Figure 8 is an enlarged sectional view taken substantially on the line8-8 of Figure l;

- Figure 9 is a sectional view taken substantialv ly on the line 9- -9of Figure 3; and 15 Figure 10 is an enlarged sectional view takensubstantially on the line Ill-i0 of Figure 3.

Referring particularly to the drawings, I have shown in Figure 1, awheel mounted on a spindle 9 and provided with a rotating brake drum to20 which is adapted to be engaged by a flexible friction member or bandgenerally designated II. This band comprises a. plurality of shoeelements such as l2, l3, ll,-l5, and it, each of the shoe elements i2,l3, l5, and i6 comprising 25 a pair of parallel web sections and a rimsection integral therewith,v the rim section having secured theretoasegment of lining adapted to contact directly with the drum. Forinstance, the shoe element l2 comprises webs i2a, a rim I21) 30 and alining segment l2c. Interposed between the ends of the shoe elements i2and I6 is an anchor I! which is secured to a backing plate i8.

The shoe elements l2, l3, l4, l5, and iii are flexibly connected to eachother, as at i9, 20, 35 2|, and 22, and are adapted to move the liningsegments into contact with the drum i0. Shoe element I4 is provided withan inwardly projecting portion 23 which serves also as a casing for afluid pressure actuating device which will 40 be hereinafter describedmore fully. The parts I 4 and 23 may be made in the form of a singlecasting, which is provided with a pair of con' neoted oval recesses IIand 32. Within these recesses there are positioned heads 34 and 35 45which are connected by the flexible sylphon supported only by 'thesprings substantially in the same way that the other shoesare sup- 55ported. Fluid is supplied to this compartment through a passage M whichis connected by a flexible hose 40 to a suitable source of fluidpressure. I

Any pressure applied to the heads 34-35 is transmitted through two pairsof curved arms 44-45 and 46-41, to toggle links 48-49, which are coupledto the adjacent shoe sections I2 and I6. The arms 44 and 45, and 46 and41, may be either flexibly coupled, or rigidly coupled to each other bythe pins 5I and 52 respectively, but in either case these points ofjuncture are pivotally connected to the adjacent shoe sections I3 andI5, by the two adjustable turn-buckle links 53 and 54.

Inasmuch as the central shoe member I4-23 is secured to the centralportion of the band, and can move freely both with respect to the drumI0 and with respect to the backing plate I8, the

reaction on said member I4-23 by reason of a fluid pressure exerted onthe heads 34 and 35 forces said member radially outward into engagementwith the drum I0; while the pressure on the heads 34 and 35 acts throughthe linkage connections 44-45, 46-41, 53-54, and 48-48 to'cooperativelyexpand the shoe sections I2, l3, I5, and I6. The brake band or ring IIis thus forced against the drum at five circumferenand 64, which actrespectively on the shoe elements I2, I6, I3, and I5; the compressionsprings Gland 68 which act on the shoe section I4; and the tensionspring 1|, which acts on the toggle links 48-48. By varying the relativestrength of these springs, the order or sequence of the application ofdifferent portions of the band to the drum may be adjusted andregulated. This adjustment is preferably such that the central portionsof the friction element II (1. e., that part formed by the shoe sectionI4) is first brought into engagement with the revolving drum surface,but any other desirable sequence of contact may be readily secured, andit is evident that by a proper regulation of the retracting springtensions, substantially instantaneous engagement of all parts of thebraking surfaces can be obtained.

The relative degree of radial thrust that is exerted respectively on theshoe section I4 and on the shoe sections I3 and I5 may be regulated bythe adjustment of the length and the radial inclination of the links 53and 54; and the cooperative action of the brake applying mechanism onthe shoe sections I2 and I6 may be also varied and controlled by theangular relationship of the toggle link elements 48 and 48 and byadjustment of the ends of the arms 46 and 41 in the slots in the links48 and 49. These adjustments I2. The member 12 is clamped to. this shoeby apair of bolts 13, whose heads are engaged by the rim I21) and whichpass through slots in the head of the said member. This head is formedwith a tapped recess into which there is inserted an adjustable screw 14that engages with a cross web 15 on the adjacent portion of the shoe I2.This afiords a means by which the relative position of the parts 12 andI2 may be easily varied to maintain any desired clearance between thebraking surfaces in the off position, without altering the operativerelationship between the interconnected elements of the brake ring andthe applying or spreading mechanism therefor. The adjustment isaccomplished by loosening the nuts of the bolts 13 and then screwing thescrew 14 inward or outward as desired.

In the use of this form of my invention, a suitable fluid (e. g. oil) isforced through the conduit 40, into the chamber 3I-32, and causes theheads 34 and 35 to move inwardly relative to the shoe element I4; andthus, through the links 44, 45, 46, 41, 48, 49, 53, and 54, and throughthe reaction on the shoe element I4 itself, expands differentcircumferential portions of the hand against the adjacentportions of thedrum, in any desired and predetermined order as may be predeterminedwhen the brake is assembled; and.

to any desired and preadjusted degree as may also be predetermined whenthe .brake is assembled.

In the embodiment of my invention shown in Figures 3 and 4, there areprovided only three series connected shoe elements (instead of five) forexpanding a substantially continuous lining or friction band II I intocontact with the drum H0. The shoe element H2, comprises aweb H20 and arim H2b; a second shoe H4 comprises a rim 4b and two side flangesH4a-H4a; and a third shoe I I6 comprises a web H611. and a rim H61), thelatter corresponding substantially to the web H211 and the rim H2b. Therims H2b, H4b, and I I6b, all cooperate to support the band III :whichforms a substantially continuous friction braking element. The band II Iis secured to the rims of the shoes in any desired manner. For example,the band may be riveted to the rims of the several shoes. The shoeelements H2. and H4, and the shoe elements H4 and 6 are pivotallyconnected at H9 and I2I, and the free end of the shoe H6 is adapted toengage directly with anchor H1.

nism therefor, by means of which this force is applied to the threeshoes H2, H4, and H6 and to the friction band member mounted thereon.The sector gear I is rotatabiy mounted on a cross pin I11 which issecured in the side flanges I I4a of the shoe I I4, and is provided withan extension arm I18. The side flanges H4a also carry a pair of crossbrackets I8I and I82, which form bearings I83 and I84 through which aworm screw I85 extends. The worm screw is actuated by means of aflexible shaft I86, and by its rotation serves to rock the gear I80 andthe lever arm I19 on the cross pin I11. The outer end of the lever I19is connected to the long arm of a bell crank lever I88 by a pair oflinks I81.

The knee and short armportion of the lever I88 is forked, andispivotally connected at its knee to a single link I89 which is, in turn,coupled to the shoe H6 by the double link I9I. The pivotally connectedends .of the links I88-HI,

hit

are supported by the outer end of a rocking guide link 190 that iscarried by the backing plate 118,.

The outer forked end of the bell crank lever 188 carries a cross pin 194by which it is pivotally secured to a slotted or" U shaped block 1'12,that is adjustably mounted on the web 112a of the shoe element 112, andis adapted to engage, at 133, with the anchor 111. The web 112a, isprovided with a slot 133 through which the pin 193 extends; and is alsoprovided with a second slot, 195, to receive a cross bolt 196 thatserves to clamp the legs of the U shaped block 112 against the sides ofthe web 112a. A rotatable cam 131 is mounted on the web 1120, and isarranged to bear against the inner end of the movable member 1112, foradjusting and maintaining it in any selected position.

In the operation or this brake, rotation of the flexible shaft 133revolves the worm 135 and rocks the operating members 1131t in acounter-clockwise direction on the cross pin 111. This action willresult in relatively opposite movements of the shoe 11 i and the linkageelements 181-433, which will tend respectively to radially expand thecenter and the ends of the brake ring memlxar 111. This expandingmovement is resisted by the tension of the springsand by altering thesetensions, the order or sequence of the engagement of difierent parts ofthe expanding members with the brake drum may be preadjusted andcontrolled in the manner previously explained. Rotation of the wheelholds the end of one of the shoe elements 112 or 11s to contact with theanchor 1-111 and thus causes a braking force to be exerted upon thedrum.

In Figures 5 and 6, I have shown a brake drum 311, within which thereare positioned the brake shoes 313 and 313; these shoes cooperating toform a band or ring member that is adapted to be moved into contact withthe drum 311 for braking the automobile. Positioned adjacent to andsubstantially closing one side of the drum 311 is a backing plate 314,to which is secured an anchor 315 interposed between the shoes 312 and313. The shoes 312 and 313 are connected by an adjusting device 316comprising a screw 316a having its ends oppositely threaded and anoperating wheel 316b therefor.

Means are provided to move the shoes 312 and 313 into contact with thedrum. This means includes a pair of fluid pressure motors 311 and 318.The motor 311 comprises a cylinder 319 and a piston 321 movable therein;and the motor 316 likewise comprises a cylinder 322 and a movable piston323. The cylinders 319 and 322 are provided with lugs 324 and 325.Pivotally connected to the lug 325 is a lever 326 which is rotatablymounted at an intermediate point in its length on a bracket 321 securedto the shoe 313. The opposite end of the lever 326 is connected by a pinand slot connection, 329 to a bell crank lever 331, which is rotatablysupported on abracket 332 secured to the backing plate 314 as at 333.The

opposite end of the bell crank lever 331 is pivotally coupled at 336 toa compression link 331 which has its opposite end pivotally connected tothe shoe 313 as at 336.

The lug 324 of the cylinder at 341, to the shoe 312 by the leversandlinks 339, 344, and 346 which are similar in all respects to thelinkage elements 326, 331, and 331.

The pistons 321 and 323 are provided with lugs 348 and 349 respectively.Connected to the lugs 348 and 349 are levers 351 and 352,'whose upper319 is connected, 7

ends are pivotally mounted between the side flanges of the shoes 312and313. Interposed betweenthe levers 351 and 352 is a compression bar 355,the ends of which serve as fulcrum points for the levers 351 and 352.

As is shown most clearly in Figure 6, the fluid motors 311 and 313 areoval in shape and the pistons fitting in the cylinders arecorrespondingly oval in shape.

Connected to the backing plate 311 and to the lower ends of the shoes312 and 313 are a pair of springs 356 and 351 which tend to pull theseends away from the drum into their normal inactive position. A secondpair of springs 353 and 353, which are connected to the shoe 312adjacent its central point and to the backing plate 31 1 aid in theretraction of the shoe 312; and a third set of springs 361 and 332,similarly connected to the shoe 313 and to the backing plate 3111 assistin the retraction of this part of the brake ring. Another set of tensionsprings, 3% and 333, which interconnect the shoes 312 and 313 and thelevers 351 and 352, and a compression spring 365 which is interposedbetween the levers 351 and 352, also aid in no air; maintaining theparts in the off position.

In the operation of this form of my improved of the compression member355 will, in turn, produce a separation of the adjacent ends of thebrake shoes'312 and 313. The cylinders 319 and 322 react in oppositedirections and exert a rotative thrust on the levers 339 and 326, thattends to move the intermediate portions of the shoes 312 and 313 towardthe drum, at points adjacent to the brackets 321 and 341. The rotativethrust on the levers 339 and 326 also exerts a turning moment on thebell crank levers 344 and 331 and this efiect is transmitted, throughthe links 331 and 346 to the lower ends of the shoes 312 and 313. Anyfluid pressure action on the cylinderpiston elements 319 -321, and322-323, will thus result in applying an expanding force to the brakeshoes at six spaced points. The sequence of application of the forces tothese different parts of the brake ring may be regulated as desired, by

proper proportioning oi the springs 356, 351, 358-, 359, 361, 362, 363,364, and 365; but I prefer that the spring tensions shall be so adjustedthat'the portion of the friction member which is opposite the anchorwill be first engaged with the drum, and that the portions which areadjacent to the anchor will be the last to be brought into contacttherewith. When this is done the following, or heel end of the brakering will always remain in fixed engagement with the anchor memberforboth directions of drum rotation-and all slamming or knocking of theparts will be eliminated.

In the modification of my invention shown in Figure '7, the levers 451and 452, instead of being pivotally connected to the ends of the brakeshoes 412 and 413, are pivotally connected to a bar ends of the levers45! and 452 are respectively connected to the levers 339a and 326a bymeans of the links 419 and 48l. The remainder of the brake applyinglinkage is the same as that shown in Figure 5.

In this last described embodiment of my invention, the link 48l alsoserves as a means for actuating the brake applying linkage, and therebymoves the friction member into engagement with the drum. As shown inFigure '7, the link 48] comprises a pair of sleeves 482 and 483 whichare provided with right and left hand internal threads, and acooperating screw 484, which engages these threaded sleeves and serves,by its rotation, to

move them away from or toward one another; and thereby change theeffective length of the link. This screw is rotated by a capstan drum485, which is pinned or otherwise properly-secured to the centralportion of the screw 484, and which is engaged by a cable 481 that iswrapped several times around this drum and is led therefrom to somesuitable operating lever on the frame of the automobile.

In the operation of this form of my invention an applying movement ofthe operating lever will rotate the drum in such direction as to movethe sleeves 482 and 483 away from each other and thereby bring differentcircumferential portions of the brake ring assembly, either successivelyor concurrently into operative engagement with the brake drum, in thesame manner as this result is accomplished in the previously describedconstruction (Figure 5). When the operating pull is released or relievedthe parts are returned to the off position shown in Figure '7, by asystem of retraction springs similar to those indicated by the referencenumerals 356, 351, 358,

359, 36!, 362 of Figure 5; and by a supplemental spring 490 that isattached to the free end of the cable 431.

It is to be understood that the above described embodiments of myinvention are for the purpose of illustration only and various changesmay be made therein without departing from the spirit and scope of theinvention.

I claim: 5

1. A brake comprising a drum; a plurality of shoes incluring a centralshoe, a plurality of intermediate shoes pivotally connected to the endsof said central shoe, and a pair of end shoes each pivotally connectedto the outer end of one of said intermediate shoes; an anchor positionedbetween the outer ends of said end shoe; 9. fluid motor carried by saidcentral shoe; a pair of actuating links each connected at one end to oneof said end shoes and interconnected at their opposite ends; a pluralityof adjustable actuating links each pivotally connected to one of saidintermediate shoes; a pair of struts each operativelyconnected to saidfluid motor at one end and each pivotally connected at its opposite endto an intermediate point of one of said first 'mentioned actuatinglinks, pivotal connections between said struts and said adjustableactuating links at points between the ends of said struts; and resilientmeans connected to said shoes and to said links for withdrawing saidshoes from motor carried by said central shoe and linkage whereby saidfluid motor actuates said shoes; and resilient means connected to saidshoes and to said links for withdrawing said shoes from drum contact. i

3. A brake comprising a drum; a plurality of shoes; a fluid motorcarried by one of said shoes; 9. pair of actuating links each connectedat one end to one of said shoes and interconnected at their oppositeends; a plurality of adjustable actuating links each pivotally connectedto one of said shoes; a pair of struts each operatively connected tosaid fluid motor at one end andeach pivotally connected at its oppositeend to an intermediate point ,of one of said first mentioned actuatinglinks, pivotal connections between said struts and said adjustableactuating links at points between the ends of said struts; and resilientmeans connected to said shoes and to said links for withdrawing saidshoes from drum contact. 4. A brake comprising a drum; a plurality ofshoes including a central shoe, a plurality of intermediate shoespivotally connected to the ends of said central shoe, and a pair of endshoes each pivotally connected to the outer end of one of saidintermediate shoes; an anchor positioned between the outer ends of saidend shoes; a fluid motor carried by said central shoe and comprising acasing, a plurality of pistons in said casing, and a plurality offlexible diaphragms each associated with one of said pistons; a pair ofactuating links each connected at one end to one of said end shoes andinterconnected at their opposite ends; a plurality of adjustableactuating links each pivotally connected to one of said intermediateshoes; a pair of struts each positioned on opposite sides of the centerof rotation of said drum and each operatively connectsaid shoes and tosaid links for withdrawing said shoes from drum contact.

5. A brake comprising a drum; a plurality or shoes including a centralshoe, a plurality or intermediate shoes pivotally connected to the endsof said central shoe, and a pair of end shoes each pivotally connectedto the outer end of one of said intermediate shoes; 'an anchorpositioned between thouter ends of said end shoe; a fluid motor carriedby said central shoe and comprising a casing, a plurality of pistons insaid casing, and a plurality of flexible diaphragms each associated withone of said pistons and linkage whereby said fluid motor actuates saidshoes; and resilient means connected to said shoes and to said links forwithdrawing said shoes from drum contact.

6. A brake comprising a drum; a plurality of shoes; a fluid motorcarried by one of said shoes and comprising a casing, a plurality ofpistons in said casing, and a plurality of flexible diaphragms eachassociated with one of said pistons; a pair of actuating links eachconnected at one end to one of said shoes and interconnected at theiropposite ends; a plurality of adjustable actuating links each pivotallyconnected to one of said shoes; a pair of struts each positioned onopposite sides of the center of rotation of said drum and eachoperatively aoeaeia' connected to one of said pistons of said fluidmotor at one end and each pivotally connected at its opposite end to anintermediate point of one of said first mentioned actuating links,pivotal connections between said struts and said adjustable actuatinglinks at points between the ends of said struts; arid resilient meansconnected to said shoes and to said links for withdrawing said shoesfrom drum contact.

'7. A brake comprising a drum; a plurality of shoes including a centralshoe, a plurality of intermediate shoes pivotally connected to saidcentral shoe, and a pair of, end, shoes each pivotally connected to theouter end ofone of said inter- -mediate shoes; an anchor positionedbetween the outer ends of said end shoe; a fluid motor carried by saidcentral shoe; a pair of actuating links each connected at one end to oneof said end shoes and interconnected at their opposite ends; a pluralityof adjustable actuating links each pivotally connected to one of saidintermediate shoes; a pair oi struts each operatively connected to saidfluid motor at one end and each pivotally connected at its opposite endto an intermediate pointof one of said first mentioned actuating links,pivotal connections between said struts and said adjustable actuatinglinks at points between, the ends of said struts; and resilient meansconnected to said shoes, and said links for withdrawing said shoes fromdrum contact, one of said end shoes being provided with a slot adjacentits outer end, an adjustable element positioned in said slot formed witha threaded bore and a bolt screwed into said bore and bearing on aportion of said shoe.

, 2*; L. 0., WADSWORTH.

